AB0705 Changes of lung function and skin fibrosis in patients with interstitial lung disease associated with systemic sclerosis on rituximab therapy - comparison of the efficacy of biosimilar Acellbia and Mabthera
Authors: L. Garzanova, L. P. Ananyeva, O. Koneva, O. Desinova, O. Ovsyannikova, M. Starovoytova, R. Shayakhmetova, A. Khelkovskaia-Sergeeva
Journal: Annals of the Rheumatic Diseases (2022)

Background Rituximab (RTX) has shown itself as an effective option in treatment of interstitial lung disease associated with systemic sclerosis (ILD-SSc). However, there is not enough data on the effect of rituximab biosimilars in patients (pts) with SSc. Biosimilars could reduce price and increase pts access to expensive, but more efficient biologic therapy. The RTX biosimilar Acellbia (ACB) was registered in Russian Federation for all indications consistent with RTX. Objectives To study changes of lung function and skin fibrosis in pts with ILD-SSc on ACB therapy in comparison with original RTX (Mabthera (MBT) during 1 year of follow-up. Methods This prospective study included 62 pts received RTX as an addition to previous therapy, when it was ineffective. The mean follow-up period was 12.9±2.2 months. 31 pts received MBT (group 1) and 31 pts received ACB (group 2). All pts had ILD. In group 1 the mean age was 42.2±12.3 years, female-25 pts (81%), the diffuse cutaneous subset of the disease had 21 pts (68%). The mean disease duration was 5.3±3.5years. 91% of pts were positive for ANA and 77% of them were positive for antitopoisomerase-1. All pts received prednisolone at a dose of 11.2±3.9 mg/day, immunosupressants (IS) at inclusion received 39% of them. The cumulative mean dose of RTX was 1.5±0.5g. In group 2 the mean age was 48.7±11.3 years, female-23 pts (74%), the diffuse cutaneous subset of the disease had 16 pts (52%). The mean disease duration was 6.2±7.1years. 88% of pts were positive for ANA, 36% of them were positive for antitopoisomerase-1. All pts received prednisolone at a dose of 10.6±4.5mg/day, IS at inclusion received 42% of them. The cumulative mean dose of RTX was 1.4±0.5g. The results are presented in the form of mean values and standard deviations, delta(Δ)-difference between the baseline parameter and follow up point, median, lower quartile and upper quartile. Results There was an improvement of all evaluated parameters in both groups: decrease of Rodnan skin score (mRSS) and activity index(EScSG-AI), increase of forced vital capacity % predicted (FVC), diffusion capacity for carbon monoxide % predicted (DLCO) and 6-minute walk distance (Table 1). Both groups managed to reduce the mean dose of prednisolone. B-lymphocyte depletion persisted in both groups. When we compared changes (Δ) of the parameters between groups - no significant difference was obtained (Table 1). Table 1. Changes of the main parameters at RXT therapy in delta (Δ); median; lower quartile; upper quartile. Parameters Group 1 Pfor Group 1 (between baseline and follow-up point) Group 2 Pfor Group 2 (between baseline and follow-up point) Pbetween group 1 and 2 Δ mRSS 4.7±5.6[2; 0; 10] 0.0001 4.3±4.1[3; 0; 8] 0.0001 NS Δ FVC, % pred 4.9±5.6[5.8; 1.8; 7.8] 0.0001 4.7±5.5[3.1; 0.9; 7] 0.0002 NS Δ DLCO, % pred 2.3±5.1[1.4; -0.6; 5.5] 0.03 2.5±3.8[2; 0.8; 4.9] 0.001 NS Δ Activity Index (EScSG-AI) 2±1.9[2; 0; 3.5] 0.0001 1.8±1.5[2; 1; 2] 0.0001 NS Δ B-lymphocyte, absolute count 0,221±0,16[0.185; 0.09; 0.33] 0.0001 0,216±0,17[0.135; 0.09; 0.34] 0.0001 NS Δ 6-minute walk distance, m 60.4±67.5[42.5; 10; 91] 0.008 55.1±42.6[52.5; 13; 90] 0.0003 NS Δ Prednisolone, mg/day 2.03±2.1[2.5; 0; 5] 0.0006 2.1±2.7[2.5; 0; 5] 0.0004 NS Cumulative mean dose of RTX, g, M±σ 1.5±0.5 - 1.4±0.5 - NS Conclusion Our prospective study showed the similar effectiveness of АСB in comparison with MBT in ILD-SSc. There was a significant improvement of lung function tests and decrease of skin fibrosis. RTX has been shown the positive effect even at low doses (less than 2 g). ACB has shown a good efficacy for therapy ILD-SSc, but studies with a large number of patients are required. Disclosure of Interests None declared